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eHam Forums => Amplifiers => Topic started by: W1EDL on June 11, 2003, 01:23:20 AM



Title: SB-201
Post by: W1EDL on June 11, 2003, 01:23:20 AM
Station ; ts-940,mfj-986 tuner,sb-201 w/harbach softkey
installed.Antenna is 130' dipole with about 90' of 450 ohm balanced feed line to the shack.
Problem; when tuning up with amp there is a very strong deflection on the cross needle meter of the tuner when
the amp relay disconnects from transmit to receive.
This does not occur when using dummy load,however.
Could the balanced feedline be causing this very strong meter deflection.
The sb-201 is a recent purchase and as of yet I have not been on the air with it.I have not had any previous
problems with my station prior to installing the amp.
Tnx for any help or suggestions you can give.

W1EDL


Title: SB-201
Post by: WB2WIK on June 11, 2003, 04:21:08 PM
Sounds to me more like the amplifier generating a strong transient signal at the moment the antenna relay releases; possibly a parasitic.  In any case, it's probably not a good thing.

Does this occur if you key the amplifier (with the transmitter) but don't actually apply any RF drive to the amplifier, e.g., key it with your exciter in the SSB mode with the mike gain turned down?

WB2WIK/6


Title: SB-201
Post by: W1EDL on June 11, 2003, 05:19:12 PM
Tnx for the response Steve,and ,yes,I do get a strong deflection on the meter when it is in SSB mode with no rf and the mic gain down.
If you prefer using email,my address is
elaval@charter.net

tnx
W1EDL


Title: SB-201
Post by: WB2WIK on June 11, 2003, 05:42:09 PM
Sounds like the amplifier creates a parasitic when the relay opens...that's a pretty common time for this to occur.

Have you checked into the improved parasitic suppression kit from AG6K?


Title: SB-201
Post by: W1EDL on June 11, 2003, 08:28:07 PM
tnx for the info and I will check AG6K web site.

W1EDL